1. Field of the Invention
The present invention relates to crop harvesting equipment and methods, and in particular, an apparatus and method of weighing harvested crop on board a harvesting machine such as, for one example, a grain combine.
2. Problems in the Art
Agriculture is a business. Viability depends on profitability. Like any business, there is a constant need to reappraise practices to see if profitability can be increased. Profitability is a significant issue in recent times. Market prices for many staple grain crops have stayed at relatively low levels. Despite inflation and increased production costs (labor, machinery, chemicals, etc.), low crop prices have economically squeezed the American farmer.
In past years, focus has been placed on increasing yield per acre to increase profitability. However, this does not guarantee economic success. Land availability and cost, labor availability and cost, and equipment costs are such that it is not possible to infinitely increase the amount of harvest or number of acres harvested. Additionally, there is, of course, a limited amount of time for any farmer, even with today's automation, to harvest crop.
The present inventor has identified one area of inefficiency that, if solved, can increase efficiency of harvesting crops. Though subtle, it can represent a significant savings in costs, labor, and stress during harvesting. At the very least, it can save money for the farmer at harvest. Hopefully, increased efficiency will increase the economy (and profitability) of harvesting and, thus, the profitability of farming as an occupation.
The following example is illustrative of the problem identified by the inventor. There is a limited window of time to harvest grain crops at maturity. Large, automated multi-row harvesting machines, sometimes called harvesters or combines, have greatly improved the efficiency of extracting the grain from the plants. Multiple rows of crops such as field corn or soybeans can be simultaneously cut, threshed, separated and cleaned on-board the machine. However, the onboard storage of the combine is much less than the total amount of crop harvested from a field. Each time the storage hopper on the harvester gets full, the combine must be unloaded.
One alternative is for the combine operator to stop and off-load the grain from the on-board hopper to another vehicle (e.g. truck, wagon, or semi-trailer). Or quite often, another vehicle, such as a tractor pulling a grain cart, travels alongside the combine and the off-loading is continuous while the combine is harvesting so that the combine can continuously run. The grain from the grain cart must then be loaded onto another vehicle, such as a semi-trailer or a wagon pulled by a tractor, for transport to a central storage location (e.g., a grain bin on the farmer's farm or a commercial grain elevator/storage facility). In any event, time and resources are spent offloading the harvested grain from the grain cart to another vehicle, such as a semi-trailer.
For a farmer who is renting land, a common financial/rental arrangement between the farmer and the landlord is known as “crop-sharing.” Under a crop-sharing agreement, the farmer/renter is responsible for costs and actions to plant and harvest the crop. Rent for use of the land is by division of the harvested crop between the farmer/renter and the landowner. A single farmer/renter may be renting land from many landowners and therefore may have several landlords with whom he divides portions of his crop. Thus, it is extremely important that an accurate record of the crop being harvested be kept so that the farmer knows how much of the crop goes to each landlord and how much he can keep for himself. Therefore, this record-keeping for dividing the crop requires that the crop be weighed immediately after it is harvested.
One method involves using the semi-trailer or wagon to drive to a commercial scale before unloading the grain at the central storage location. The farmer then keeps track of the weight of each truck load from the commercial scale so that the farmer/renter and the landlord can make a proper division of the crop at a later time. However, this process involves several inefficiencies, such as extra time, labor, and fuel costs, especially if the commercial scale is many miles away from the field where harvest is occurring. Therefore, this alternative is disfavored by many renters/farmers.
Another attempt to provide this information has been the use of yield monitors. For example, there are a variety of yield sensors or monitors available commercially and installed or installable on combines. Examples are U.S. Pat. Nos. 6,460,008 and 6,584,424. The yield monitors attempt to derive the amount of crop coming into the harvester in the threshing, separating, cleaning subsystem and make an estimation of amount of yield per acre. While they can provide reasonable estimates of amount of grain at certain times, at other times they can produce substantial errors. There are many variables that go into yield monitoring and conversion to amount harvested, and they have been found to be unreliable. Yield monitors measure grain flow into the combine, i.e., a volumetric flow measurement which can be imprecise in itself unless the monitor is calibrated correctly. Therefore, to get weight from these yield monitors, the volumetric measurement must be converted using several variables, such as density and moisture of the grain. Therefore, they need to be calibrated carefully for each field and/or environmental conditions. One example of their lack of consistency or reliability is the lack of universal acceptance of the same by crop insurers or other third parties. One measurement may be within unacceptable range of accuracy. The next, though, they might be off substantially (e.g., a thousand or more pounds).
Thus, trying to weigh grain on board a combine is not trivial. Some how you would have to isolate the grain hopper from the remainder of the combine. The hopper holds thousands of pounds of grain and is connected to the remainder of the combine body. Additionally, the combine, at least when moving, is experiencing substantial vibration and forces. The development and reliance and yield monitors has been previously noted. They have been found too inconsistent, however.
Presently, many farmers use the grain cart as the step in the harvest process where the grain is weighed so that a record of the crop can be kept for dividing it between the landlord and farmer/renter. Some grain carts include sensors from which the weight of the grain can be derived. One example is grain carts that utilize strain gauges or load cells between the grain cart hopper and the trailer hitch and trailer wheels. By calibration, an estimate of the weight of the hopper when empty can be derived. Then, when full of grain, the weight of the hopper can be subtracted and the weight of the grain in the hopper estimated. The grain cart operator can record the weight of the crop in the hopper, and repeat the same for all of the crop from a field to record a cumulative weight of crop for the field. Types of these grain carts are commercially available. There can be accuracy problems with this arrangement, however. Because loads on all wheels of the trailer or cart, as well as on the tractor hitch connection between the cart and tractor must be summed, the trailer or cart must be on fairly level ground to get a reasonably accurate reading. If not, or if there is some abnormal strain or load on the hitch (like when the cart/trailer is not on level ground), it can materially affect the readings and the accuracy of the weight of the grain in the trailer hopper. There were concerns whether load cells could satisfactorily work to derive weight of what is held in the hopper of a grain cart. They have to measure significant loads on the order of tens of thousand of pounds, and it is difficult to place the load cells within the physical structure of the grain cart. The grain carts also travel over bumps, rocks, and other variations in terrain, and experience substantial vibrations and other forces. Based on information and belief, placement of load cells in grain carts has been possible because they do not have driven axles or driven wheels. Grain carts, like other trailers, only have non-driven axles and wheels that are pulled along by the tractor.
The basic theory of load cells on a grain cart is that load cells can be made structurally strong enough to fit between the non-driven wheels and the axels of the grain cart such that the frame and hopper of the grain cart are suspended on the load cells. The load cells essentially have structural integrity to become part of the non-driven dead axles. Of course, this does not work for self-propelled combines because there are driven wheels that require a drive train. Additionally, the mass of the unloaded combine is usually bigger than the grain cart and would not be supported on simply one load cell per wheel. Therefore, accurate on-field weighing has conventionally been constrained to grain carts with load cells.
But using the intermediate step of the tractor/grain cart combination to weigh the harvested grain costs the farmer tens of thousands of dollars every year. Grain carts cost on the order of $60,000. A tractor large enough to pull the grain cart costs on the order of $100,000. A hired worker to operate the tractor and grain cart costs on the order of $7000 just during the harvest season. The fuel cost for the tractor pulling the grain cart can be on the order $8000 per year and continues to escalate with rising fuel costs.
Thus, if fuel, labor, and equipment depreciation costs are added together, the cost of operating a tractor/grain cart combination can be approximately $30,000 per year for a grain cart that is servicing two combines operating simultaneously in the same field.
In addition to these significant monetary costs, using a grain cart to weigh the grain from the combine forces the farmer to operate all of his combines in the same field. It would be grossly inefficient and not practical to have the grain cart traveling between fields trying to catch the grain from multiple combines if they were operating in different fields which could be miles apart.
A still further important consideration is soil compaction. A large second vehicle, like a grain cart and four wheel drive tractor combination is very heavy (e.g., tens of thousands of pounds on each wheel and axle), especially when the grain cart is loaded. This second vehicle adds significant soil compaction to the field. It is widely acknowledged that soil compaction increases costs in preparing the field for the next crop (e.g., more difficult to till), and can even materially adversely affect yield from the field because of the compacted soil bed.
As can be readily seen, using a tractor and grain cart procedure includes substantial labor, fuel, and equipment costs as well as causing soil compaction and other inefficiencies.
It also should be noted that harvesting places certain physical and physiological stresses on those involved. For example, preferably a crop is harvested as quickly as possible. Most farmers, by practicalities, do not have unlimited equipment and labor resources. Therefore, many work long, continuous hours; sometimes around the clock. An improvement in operator ease during harvest can beneficially impact those issues.
The above examples are but a few illustrations of the need identified in the art for a more efficient way to remove and weigh grain from a field during harvesting. Additionally, a real need in the art exists for a better way of removing and weighing grain from the field which requires fewer people and/or less fuel and/or less time and/or less equipment costs.
The present invention solves these and other problems by eliminating an intermediate step during harvest. With the present invention, the combine can now accurately weigh the grain being harvested. The farmer/renter no longer needs an expensive grain cart (on the order of $60,000 to 80,000) with an expensive tractor pulling it (on the order of $100,000.00) to weigh the grain before loading the grain on to a truck to be hauled away. Elimination of the grain cart for weighing grain eliminates significant fuel and equipment costs, reduces soil compaction by having one less implement in the field, and reduces labor costs by reducing the number of workers required during the harvest process.